Range finder



June 4, 1946.

J. ,MlHALYI RANGE FINDER Filed March 13, 1945 6 Sheets-Sheet I J O.SEPH MIHALY] W BY ATTY & A CT J. MlHALYi RANGE FINDER June 4, 1946.

Filed March 15, 1943 6 Sheets-Sheet2 JOSEPH MIHALYI INVENTOR ATT'Y & AG'T 6 Sheets-Sheet 3 J. MIHALYI RANGE FINDER Filed March 13, 1943 June 4, 1946.

J; M lHALYl RANGE FINDER June 4, 1946.

Filed March 15, 194s 6 Sheets-Sheet 4 JOSEPH MIHALY] INVENTOR ATT'Y & AG'T,

June 4, 1946. MHALY] -2 ,401,705

'RANGE FINDER Filed March 15, 1943 3 -e Sheets-Sheet 5 JOSEP MHMLYT INVEN TOR flflad BYW:

J. MIHALYI RANGE FiNDER June 4, 1946.

Filed March 15, 1945 s Shpts-Shei e JOSEPH MIHALKI ATT'Y& AGT

Patented June 4, 1946 OFFICE RANGE FINDER Joseph Mihalyi, Rochester, N. Y., assignorto Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application March 13, 1943, Serial No. 479,097

14 Claims. 1

p This invention relates to range finders.

This is Case G of a series of applications relating to this same subject. The series includes the following:

Title Filed Inventors Binge finder construe- Range finders-Case B Range findeis-Case C Range flnders-Oase D- Range finders-Case E Range findersCase 1.. Range finders-Case J.

Range finders-Case M,

Oct.

Oct. 10, 1942 Jan. Jan. Jan. Jan. Jan. Mar. Mar. Mar. 13,19 Mar. Mar. Mar. 13,1943 June 23,1943 June 23,1943 June 23, 1943 Oct. 5,1943 Oct. 29,1943

Mihalyi.

Do. Do.

Do. Mihalyi, MacNeille. Mihalyi, Tuttle. Mih

Mount for optical element on. Range finders-Case A Range finders-Case F Range findersCase H.

Range findersGase K. Range finders-Case L Range finders-Case N. Range finders-Case O Range finders-Case P Range finders-Case T The present Case G is not limited in any way to autocollimatin range finders such as described in other cases of this series, but is applicable to all range finders in which one or more objectives are used for forming in comparison planes, images of the object being ranged. The present invention is particularly useful however with autocollimating range finders since both features are fundamentally time savers. In coincidence range finders the comparison planes are coplanar and instereo range finders the comparison planes are viewed separately by the two eyes of the observer. Inall range finders of this general type it is advantageous to have relatively high magnification to give large images for concidence or stereo comparison. Such large magnification is accompanied by a relatively small field of view so that considerable time is often consumed in attempting to get the object being ranged within the field of view of the finder.

The present invention has for its object the provision of means to permit rapid sighting of the finder which, of course, is of utmost importance when ranging on an aeroplane, for example, at which time every moment counts.

Specifically it is an object of the invention to provide a wide field of view in a range finder, without interfering with the magnification necessary. for easy judging of coincidence or stereo depth. It is an object of a preferred embodiment of the invention to provide this wide field of view momentarily until the finder is aligned and to per- 2 mit the wide field providing means to be o'utof the way while actually ranging.

On the other hand, when applied to camera range finders, the opposite is required since nly momentary ranging is usually needed and the view finding must be more carefully executed.

According to the present invention these objects are provided by inserting in the optical system of a range finder a wide field producing means which is positionable in and out of the optical system. The image formed while this auxiliary system is inserted, is, of course, of lower magnification. The normal operation of the de-; vice is to hold the view finder in position until the small image of the areoplane, for example, is brought into the field of view and fairly well centered. At this time, one of the viewing point images and possibly the other, if the auxiliary viewer does not interfere completely with one of the range finder beams, are also centered in the field. The auxiliary viewer is then allowed to snap out of the range finder system and the two relatively large images are compared for ranging in the normal way.

There are two main forms of this invention depending on whether the auxiliary viewer is positioned in a collimated beam or in a converging beam-following one of the range finder objectives. If a single objective is used, the invention preferably takes the form of an inverted Galilean telescope inserted in at least one of the collimated beams entering the single objective. Of course, the light fromthe object being ranged entering the auxiliary finder system need not be the same as that entering either of the viewing points of the range finder. In fact, in general the finder system has a separate viewing point so that its field of view is independent of the apertures imposed on the regular range finder viewing points.

The second species of the invention is particularly useful with coincidence or stereo range finders which have two relatively long focal length objectives positioned near the viewing points of the range finder. According to this/species of the invention an objective of shorter focal length is positioned to receive light at a third viewing point and to focus it in one of the comparison planes. Thus this auxiliary objective is between one of the main objectives and its comparison plane. In actual practice this is best accomplished by having the short focal length objective facing toward the object being ranged and at an intermediate viewing point and by having a reflector which is normally to one side of the range finder optical system but which may be ily for viewing. I'Ihepart which is .insertable in the range finder system is preferably urged out of the range finder system by some spring means against the force'of which the viewer is moved manually for momentary viewing. I

Having a third viewing point between the main two, is preferable whatever type of range finder or viewer is used since it permits more compact arrangement of the invention and permits the viewer to be operated by hand while supporting the instrument by the same hand. I find that.

most rapid operation of, the instrument is at tainable when the main images of the object being ranged are both visible, although one of them only partly, while the viewer is being operated.

In one preferred embodiment of the invention the range finder is provided with two handles adjacent to one of which is located a button or lever whichim'ay be=operatedto move the viewer system into position andto' hold it there against this spring force. 7

The ranging knob may be near either of the handles since-ranging is done after the viewer is released but preferably isnear the other handle soth'at the operator may begin ranging even before theviewer system is allowed to move out of the way. Applications; Serial Numbers 461,584 and 461.585 mentioned'above are drawn to such features "but'not in combination with the present main invention.

Other objects and advantages of the invention and-the method of'operation thereof will be fully understood from the following descriptionwhen read in connection with the accompanying drawiii-gain which: e j

Fig. 1 is aperspective view of the-optical system of one embodiment of the invention, Figs. 1A andlBbeing the views through the eyepiece of the instrument respectively when view finding and when ranging, v

Fig. 2 is a plan view of a range finder' incorporating the optical system shown in Fig. 1,

531 .3; ill-ustratesanother embodiment of the invention applied to a single objective range. finder; Fig. 3A being v an enlarged view of one detail of the system shown ihFig'. 3, 7

Figs. 4A-and-4B are views'thro'ugh'the eyepiece of thesystem shown in Fig. .3respectively when view" finding and when ranging;

Figs. 5 and 6, each shown in two' parts for clarity. are respectively plan and elevation views partly in'sectionof a range finder incorporating theoptical system shown perspectively in Fig. 3,

Figs. '7'; 8 and 9'"are vertical cross sections at different pointsalong the finder. shown in Figs. 3 too;

Fig;- lflfis aperspective view of astereo range finder'incorporating the invention,

Fig. 11 shows a detail alternative toone included in- Fig; 3.-

In the embodiment of the invention shown in Figs.- 1- and' 2- light from a distant object represented by small aeroplanes .20 is directed toward comparison planes by pentaprisms 2| I and is brought to focus'in those planesby objectives 22 and 23; Light from objective 22=enters a rhomb 2-61 and is reflected by a' prism 25 and another prism-2"! down to the. mirrored halffllof an interface in the prism assembly, whence it is reflected upward to a comparison plane at a slight angle to this surface 3| which comparison plane is viewed through an eyepiece 32 by the eye 33 of an observer. Similarly, light from the objective 23 is reflected by a prism 24 and another prism 28 upward through a clear area 36 in the interface described above and thence through the eyepiece 32. To permit the range finder to be adjusted for coincidence, the prism unit is carried by a support 39, shown best in Fig. 2, and'is moved in the direction indicated by the double headed arrow 35 (Fig. l) by rotating the knob 36. When the images 48 and 49 are in coincidence as shown in Fig. 1B the range may be read by" an index 3'! against a scale 38"carried by the knob 36'.

Of course, the images 48 and 49 are quite large and the field of view of the instrument is relatively small so that it is difficult to align the range finder on'theobject being ranged. in the split second available for ranging an aeroplane. According to the invention, an auxiliary objective of shorter focal length is positioned atan intermediate viewing point. In larder to find-theviewand line-up the range finder, an optical square comprising mirrors 42 and 43 carried by a support i4 is held, against. theiforce of a spring 7496, in the range finder beam coming from the in this position by theyfinger of the operator engaging. a small grip. 55 on the mount .44. The field of view ofthe objective 4|; as defined in thecom; parison plane seen through. theeyepiece 32, is many times larger than that of the-objective 23. In fact, since the fieldof view of the; eyepiece .32 is the limiting factor, the: field. of view' is. increased by the same. factor. that themagnifica, tion is decreased. -To operate the device, the auxiliary finder system is held as shown in Fig. 1. and; aslshown by solid lines in Fig. 2. untilthe image 41. is seenzand is. brought moreor less to thelcenter of the field, by; orienting, the. whole. instrument properly. As. soon, as the image 41 is somewhere in the center-otthe=field,- atiwhich timethe image 48 starts to come into the field of view;,.the gripe? is released.and the'mirrorsfl and..43- swiing, under theaction. oftthe springrdt to: oneside of the range finder beamas' shown in dotted linesiin Fig. 2.. At this; time-itis quiteeasy to. range the object.

In: Figs; 3' to; 9- light'; frornthe' object being rangedfis: reflected by"- arotatablezmirror 5| to form one. range finder beam which .is practically collimated and by. arsemi-transparent mirror: 52 to form the other range finder beamwhichzis also collimatedp Thesetwo rangeiifindersbeams are brought to focusbya simple'obje'ct'ive i3 and .an erecting prism 54 tofo'rm images 6 'i1an'd68l in tates a disk 82 which-carries a coinci'dence*line-63 and a, scale, all of which are described indetail in Cases E' andF Gr m-118 5811853 Light from a 1ampi$fi as-refiected by mirror Bij passes upward throughthe coincidence line 63 and is-refiec-ted by a small erecting prism Minto the optical system i of the range finder. This light is collimated by objective 53 and is then reflected by a prism 65 cemented'to the mirror 5|, and a clove prism 66 cemented to the semi-transparent mirror 52, back through the objective 53 to form an image 63 in the comparison planes.

According to the invention an auxiliary finder system is provided in the form of an inverted Galilean telescope consisting of a negative lens II :at a viewing point intermediate to those of the range finder, a mirror I3 and a positive lens I2. When the auxiliary system is arranged as shown in Fig. 3 and as shown by broken lines in Fig. 5, part2, animage 89 shown in Fig. 4A, of reduced size is formed in the comparison plane. This small image permits the object to be brought into the field of view and fairly well centered. It will be noted in Fig. 4A that no image 63 of the coincidence line is seen because when finding the field of view, there is no point in turning on the. lamp 60. Also, both images 6'1 and 68 are .visible in Fig. 4A, but one of them is of diminished intensity because the mirror I3 and lens I4 interfere with part of the collimated beam from the mirror 5!. However, all of the beam is not so interrupted and it is quite possible to get coincidence while the small image 69 is still in the field of view. However, it is preferable to let this small image go as soon as the instrument is aligned and this is provided by allowing the auxiliary system to move to one side of the object beam. The lens I2 and the mirror I3 are carried by a support 14 which consists of a lower portion part of which constitutes a stop 84 and an upper portion I5 both of which portions engage a vertical rod 86 to rotate thereone The rod 86 is supported by a member 85 fastened to the housing I62 of the range finder and having two detents, one of which is the side of the member 85 to engage the stop 84 when the auxiliary system is moved to one side of the range finder system and the other, 82, arranged to engage a stop 8| which consists of part of the member I5, when the auxiliary system is moved into the position shown in Fig. 3 and by broken lines in Fig. 5. A wire shaped member I6 having a spring shock absorber II therein engages the member I5 so that, against the force of a spring 83 which engages both the support 85 and the member I5, it can pull the member I5 and the support I4 together with the lens I2 and mirror I3 into the position shown in Fig. 3. This operation is provided by an arm I8 carried by a shaft I9 which may be rotated by pressure on a button 86.

The button 80 is located near one of the handles I of the instrument so that the button 80 may be operated momentarily by the left thumb of the operator and then released as soon as the instrument is properly aligned. At this time the spring 83 rotates the member I4 and I until the stop 34 strikes the edge of the support 85 and holds the auxiliary system in the position shown by solid lines in Fig, 5, part2. At this time the right hand of the operator holding the other handle Illl of the instrument operates the knob 89 for ranging.

A stereoscopic range finder is shown in Fig. 10 in which light from the object being ranged is received by pentaprisms H0 and is focused by objectives III in comparison planes 2 carrying stereo fiducial marks H3 which indicate the range. The object images thus formed and the stereo marks I I3 are viewed binocularly by prisms H4 and eyepieces 5 by the right and left eyes H6 of an observer. According to the invention an auxiliary objective I20 of shorter focal length than the objective III is positioned at an intermediate viewing point to send light to the left eye image plane by means of a removable mirror system made up of mirrors 42 and 43', identical; in construction and operation to those shown in Fig. 1. i

Fig. 11 illustrates a less preferable embodiment of the invention in which the collimated beam from the mirror 5| of Fig. 3 forms the view finder beam; That is, the view finder system uses the same viewing point as one of the rangefinder beams. In Fig. 11 a negative lens I30 and'a positive lens I3! are carried by a support I32 which is normally held, by a spring I34, to one side of the collimated beam coming from the mirror 5| of Fig. 3. This inverted Galilean telescope may be moved against the force of the spring34 by pressure on a handle I33 so that it intercepts the collimated beam and introduces decreased magnification with a wider field of View. However, the field of View is then limited by the aperture of the viewing point near the mirror 5! and cloes not necessarily fill the viewing plane 55-, at this lower magnification. Thus the auxiliary viewing point arrangement shownin Fig. 3 is preferable although the arrangement in Fig. 11 is somewhat simpler. i i I 1 Having thus described the preferred embodi ments of my invention, I wish to point out that it is not limited to these structures but is of the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:

1. A range finder of the type having two spaced viewing points at which substantially collimated beams of light are received from the object being ranged, an optical system including at least one objective for directing and focusing the two collimated beams forming images in comprison planes and a ranging adjuster, said range finder being characterized by means insertable alternatively in and out of said optical system for forming a real image of the object at lower magnification in one of said planes while inserted in said system to produce a wider field of view.

2. A range finder according to claim 1 in which said wider field producing means is an inverted Galilean telescope insertable in at least one of than the first mentioned objective and reflecting means in alignment with the auxiliary objective for reflecting light from the object being ranged into focus in one of the planes without going through said first mentioned objective.

4. A range finder according to claim 1 including spring means for urging at least part of said wider field producing means out of said optical system and manually operable means for moving said part into said optical system against the spring urging force.

5. A range finder according to claim 1 including a third viewing point between the other two for receiving collimated light from the object being ranged, at least one lens positioned at said third viewing point constituting part of said wider field producing means and a reflector constituting said insertable means movable alternatively to two positions in one which it is optically ineffective relative to the range finder and in the other of which it receives light from the third viewing point and reflects itto. one of the comparison planes; g

' 6i A range finderaccordi-ng to claim 1 in which one of the object beams is-unaffected by the wider field'producing means and the other object beam is only: partly cut off whil'e thawider field producingmeans is in said system.

7. A single objective range finder of the type having two viewing point-reflectors for reflecting beams from the object being ranged into alignment through an objective to form real-images for comparison characterized byan inverted'Galilean telescope positionable between the reflectors in one of 'the' beams for giving an image of the object of lower magnification than that produced by'the'otherbeams and-means for moving said telescope to one side ofsaid one of the beams.

8. A range finder according to claim '7 in which the telescope includes a reflector and has its front lens facing the object when in said one of the beams. v

9. A-range finder according toclaim 7 in which spring means urge said telescope toone side of said one ofthe beams and manually operable meansare provided for holding the telescope in saidb'eam against the force of the spring means.

10. A' range finder of the type having two viewing-poi nts at which beams of light are received from the object being ranged and two relatively longfocal length objectives-for forming in com parison planes images of'the object'being ranged characterized by a relatively short focal length objective at 'a viewing point between the other two and reflecting means positionable in one of the object beams to reflect av third object beam through thesho-rt focal length objective toward, and into focus in; one of thecomparison planes and means for moving and hold ing' outl of saidone of the beams at least all of said re flecting means andishort focal length objective Which-is positionable in saidone ofi the beams.

1l.-A' range finder accordingto' claim 10- in which said comparison planes are coincident.

12'. A range finderiaccording to claim, 10 in which said comparison planes. are viewed stereoscopically.

13; A range finder according'to claim I. having twohandlesand adjacent to one o'f the han-' dles manually operable means for moving said wider 'field producing means relative to' the opticalisystem. V

14. A range finder according to claim 1 having two handles, spring means-for urging at l'east part of said wider field producing means out of said optical system and, adjacent to one of'the handles manually-operable means for movin'gsaid part into the opticalsystem againstf the-spring urging force.

JOSEPH MIHALYI. 

